The Apple store is currently showing the white MacBook as “new” and shipping with NVidia 9400m graphics – the same chipset used in the new aluminum MacBooks. The speed is now also just 2.0 Ghz, down from 2.1 Ghz previously.

It looks as though Apple has decided to move that model over to the new platform used in all the other current generation MacBooks.
However: the white model retains its Firewire 400 port, which might actually make the “cheap” plastic MacBook more interesting to some customers than the Firewire-less aluminum models.
